In 1997, a Cambrian fossil was unearthed in Chengjiang, Yunnan. It lay quietly in the fossil library of Northwest University and no one cared about it until it was discovered by Professor Shu De Gan. It caused a sensation around the world and was called "the world's number one fish". How many mysteries are left for mankind in the Cambrian period? What kind of shocking changes are recorded in the ancient stalagmites?